WebTestBase.php

<?php

/**
 * @file
 * Definition of \Drupal\simpletest\WebTestBase.
 */

namespace Drupal\simpletest;

use Drupal\block\Entity\Block;
use Drupal\Component\FileCache\FileCacheFactory;
use Drupal\Component\Serialization\Json;
use Drupal\Component\Serialization\Yaml;
use Drupal\Component\Utility\Html;
use Drupal\Component\Utility\NestedArray;
use Drupal\Component\Utility\UrlHelper;
use Drupal\Core\Cache\Cache;
use Drupal\Component\Utility\SafeMarkup;
use Drupal\Core\Database\Database;
use Drupal\Core\DrupalKernel;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\EventSubscriber\MainContentViewSubscriber;
use Drupal\Core\Render\Element;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\Session\AnonymousUserSession;
use Drupal\Core\Session\UserSession;
use Drupal\Core\Site\Settings;
use Drupal\Core\StreamWrapper\PublicStream;
use Drupal\Core\Url;
use Drupal\node\Entity\NodeType;
use Symfony\Component\HttpFoundation\Request;

/**
 * Test case for typical Drupal tests.
 *
 * @ingroup testing
 */
abstract class WebTestBase extends TestBase {

  use AssertContentTrait;

  use UserCreationTrait {
    createUser as drupalCreateUser;
    createRole as drupalCreateRole;
    createAdminRole as drupalCreateAdminRole;
  }

  /**
   * The profile to install as a basis for testing.
   *
   * @var string
   */
  protected $profile = 'testing';

  /**
   * The URL currently loaded in the internal browser.
   *
   * @var string
   */
  protected $url;

  /**
   * The handle of the current cURL connection.
   *
   * @var resource
   */
  protected $curlHandle;

  /**
   * The headers of the page currently loaded in the internal browser.
   *
   * @var Array
   */
  protected $headers;

  /**
   * The cookies of the page currently loaded in the internal browser.
   *
   * @var array
   */
  protected $cookies;

  /**
   * Indicates that headers should be dumped if verbose output is enabled.
   *
   * Headers are dumped to verbose by drupalGet(), drupalHead(), and
   * drupalPostForm().
   *
   * @var bool
   */
  protected $dumpHeaders = FALSE;

  /**
   * The current user logged in using the internal browser.
   *
   * @var \Drupal\Core\Session\AccountInterface|bool
   */
  protected $loggedInUser = FALSE;

  /**
   * The "#1" admin user.
   *
   * @var \Drupal\Core\Session\AccountInterface
   */
  protected $rootUser;


  /**
   * The current cookie file used by cURL.
   *
   * We do not reuse the cookies in further runs, so we do not need a file
   * but we still need cookie handling, so we set the jar to NULL.
   */
  protected $cookieFile = NULL;

  /**
   * Additional cURL options.
   *
   * \Drupal\simpletest\WebTestBase itself never sets this but always obeys what
   * is set.
   */
  protected $additionalCurlOptions = array();

  /**
   * The original batch, before it was changed for testing purposes.
   *
   * @var array
   */
  protected $originalBatch;

  /**
   * The original user, before it was changed to a clean uid = 1 for testing.
   *
   * @var object
   */
  protected $originalUser = NULL;

  /**
   * The original shutdown handlers array, before it was cleaned for testing.
   *
   * @var array
   */
  protected $originalShutdownCallbacks = array();

  /**
   * The current session ID, if available.
   */
  protected $sessionId = NULL;

  /**
   * Whether the files were copied to the test files directory.
   */
  protected $generatedTestFiles = FALSE;

  /**
   * The maximum number of redirects to follow when handling responses.
   */
  protected $maximumRedirects = 5;

  /**
   * The number of redirects followed during the handling of a request.
   */
  protected $redirectCount;

  /**
   * The kernel used in this test.
   *
   * @var \Drupal\Core\DrupalKernel
   */
  protected $kernel;

  /**
   * The config directories used in this test.
   */
  protected $configDirectories = array();

  /**
   * Cookies to set on curl requests.
   *
   * @var array
   */
  protected $curlCookies = array();

  /**
   * An array of custom translations suitable for drupal_rewrite_settings().
   *
   * @var array
   */
  protected $customTranslations;

  /**
   * Constructor for \Drupal\simpletest\WebTestBase.
   */
  function __construct($test_id = NULL) {
    parent::__construct($test_id);
    $this->skipClasses[__CLASS__] = TRUE;
  }

  /**
   * Get a node from the database based on its title.
   *
   * @param $title
   *   A node title, usually generated by $this->randomMachineName().
   * @param $reset
   *   (optional) Whether to reset the entity cache.
   *
   * @return \Drupal\node\NodeInterface
   *   A node entity matching $title.
   */
  function drupalGetNodeByTitle($title, $reset = FALSE) {
    if ($reset) {
      \Drupal::entityManager()->getStorage('node')->resetCache();
    }
    $nodes = entity_load_multiple_by_properties('node', array('title' => $title));
    // Load the first node returned from the database.
    $returned_node = reset($nodes);
    return $returned_node;
  }

  /**
   * Creates a node based on default settings.
   *
   * @param array $settings
   *   (optional) An associative array of settings for the node, as used in
   *   entity_create(). Override the defaults by specifying the key and value
   *   in the array, for example:
   *   @code
   *     $this->drupalCreateNode(array(
   *       'title' => t('Hello, world!'),
   *       'type' => 'article',
   *     ));
   *   @endcode
   *   The following defaults are provided:
   *   - body: Random string using the default filter format:
   *     @code
   *       $settings['body'][0] = array(
   *         'value' => $this->randomMachineName(32),
   *         'format' => filter_default_format(),
   *       );
   *     @endcode
   *   - title: Random string.
   *   - type: 'page'.
   *   - uid: The currently logged in user, or anonymous.
   *
   * @return \Drupal\node\NodeInterface
   *   The created node entity.
   */
  protected function drupalCreateNode(array $settings = array()) {
    // Populate defaults array.
    $settings += array(
      'body'      => array(array(
        'value' => $this->randomMachineName(32),
        'format' => filter_default_format(),
      )),
      'title'     => $this->randomMachineName(8),
      'type'      => 'page',
      'uid'       => \Drupal::currentUser()->id(),
    );
    $node = entity_create('node', $settings);
    $node->save();

    return $node;
  }

  /**
   * Creates a custom content type based on default settings.
   *
   * @param array $values
   *   An array of settings to change from the defaults.
   *   Example: 'type' => 'foo'.
   *
   * @return \Drupal\node\Entity\NodeType
   *   Created content type.
   */
  protected function drupalCreateContentType(array $values = array()) {
    // Find a non-existent random type name.
    if (!isset($values['type'])) {
      do {
        $id = strtolower($this->randomMachineName(8));
      } while (NodeType::load($id));
    }
    else {
      $id = $values['type'];
    }
    $values += array(
      'type' => $id,
      'name' => $id,
    );
    $type = entity_create('node_type', $values);
    $status = $type->save();
    node_add_body_field($type);
    \Drupal::service('router.builder')->rebuild();

    $this->assertEqual($status, SAVED_NEW, SafeMarkup::format('Created content type %type.', array('%type' => $type->id())));

    return $type;
  }

  /**
   * Builds the renderable view of an entity.
   *
   * Entities postpone the composition of their renderable arrays to #pre_render
   * functions in order to maximize cache efficacy. This means that the full
   * renderable array for an entity is constructed in drupal_render(). Some
   * tests require the complete renderable array for an entity outside of the
   * drupal_render process in order to verify the presence of specific values.
   * This method isolates the steps in the render process that produce an
   * entity's renderable array.
   *
   * @param \Drupal\Core\Entity\EntityInterface $entity
   *   The entity to prepare a renderable array for.
   * @param string $view_mode
   *   (optional) The view mode that should be used to build the entity.
   * @param null $langcode
   *   (optional) For which language the entity should be prepared, defaults to
   *   the current content language.
   * @param bool $reset
   *   (optional) Whether to clear the cache for this entity.
   * @return array
   *
   * @see drupal_render()
   */
  protected function drupalBuildEntityView(EntityInterface $entity, $view_mode = 'full', $langcode = NULL, $reset = FALSE) {
    $ensure_fully_built = function(&$elements) use (&$ensure_fully_built) {
      // If the default values for this element have not been loaded yet, populate
      // them.
      if (isset($elements['#type']) && empty($elements['#defaults_loaded'])) {
        $elements += \Drupal::service('element_info')->getInfo($elements['#type']);
      }

      // Make any final changes to the element before it is rendered. This means
      // that the $element or the children can be altered or corrected before the
      // element is rendered into the final text.
      if (isset($elements['#pre_render'])) {
        foreach ($elements['#pre_render'] as $callable) {
          $elements = call_user_func($callable, $elements);
        }
      }

      // And recurse.
      $children = Element::children($elements, TRUE);
      foreach ($children as $key) {
        $ensure_fully_built($elements[$key]);
      }
    };

    $render_controller = $this->container->get('entity.manager')->getViewBuilder($entity->getEntityTypeId());
    if ($reset) {
      $render_controller->resetCache(array($entity->id()));
    }
    $build = $render_controller->view($entity, $view_mode, $langcode);
    $ensure_fully_built($build);

    return $build;
  }

  /**
   * Creates a block instance based on default settings.
   *
   * @param string $plugin_id
   *   The plugin ID of the block type for this block instance.
   * @param array $settings
   *   (optional) An associative array of settings for the block entity.
   *   Override the defaults by specifying the key and value in the array, for
   *   example:
   *   @code
   *     $this->drupalPlaceBlock('system_powered_by_block', array(
   *       'label' => t('Hello, world!'),
   *     ));
   *   @endcode
   *   The following defaults are provided:
   *   - label: Random string.
   *   - ID: Random string.
   *   - region: 'sidebar_first'.
   *   - theme: The default theme.
   *   - visibility: Empty array.
   *   - cache: array('max_age' => Cache::PERMANENT).
   *
   * @return \Drupal\block\Entity\Block
   *   The block entity.
   *
   * @todo
   *   Add support for creating custom block instances.
   */
  protected function drupalPlaceBlock($plugin_id, array $settings = array()) {
    $settings += array(
      'plugin' => $plugin_id,
      'region' => 'sidebar_first',
      'id' => strtolower($this->randomMachineName(8)),
      'theme' => $this->config('system.theme')->get('default'),
      'label' => $this->randomMachineName(8),
      'visibility' => array(),
      'weight' => 0,
      'cache' => array(
        'max_age' => Cache::PERMANENT,
      ),
    );
    $values = [];
    foreach (array('region', 'id', 'theme', 'plugin', 'weight', 'visibility') as $key) {
      $values[$key] = $settings[$key];
      // Remove extra values that do not belong in the settings array.
      unset($settings[$key]);
    }
    foreach ($values['visibility'] as $id => $visibility) {
      $values['visibility'][$id]['id'] = $id;
    }
    $values['settings'] = $settings;
    $block = entity_create('block', $values);
    $block->save();
    return $block;
  }

  /**
   * Checks to see whether a block appears on the page.
   *
   * @param \Drupal\block\Entity\Block $block
   *   The block entity to find on the page.
   */
  protected function assertBlockAppears(Block $block) {
    $result = $this->findBlockInstance($block);
    $this->assertTrue(!empty($result), format_string('Ensure the block @id appears on the page', array('@id' => $block->id())));
  }

  /**
   * Checks to see whether a block does not appears on the page.
   *
   * @param \Drupal\block\Entity\Block $block
   *   The block entity to find on the page.
   */
  protected function assertNoBlockAppears(Block $block) {
    $result = $this->findBlockInstance($block);
    $this->assertFalse(!empty($result), format_string('Ensure the block @id does not appear on the page', array('@id' => $block->id())));
  }

  /**
   * Find a block instance on the page.
   *
   * @param \Drupal\block\Entity\Block $block
   *   The block entity to find on the page.
   *
   * @return array
   *   The result from the xpath query.
   */
  protected function findBlockInstance(Block $block) {
    return $this->xpath('//div[@id = :id]', array(':id' => 'block-' . $block->id()));
  }

  /**
   * Gets a list files that can be used in tests.
   *
   * @param $type
   *   File type, possible values: 'binary', 'html', 'image', 'javascript',
   *   'php', 'sql', 'text'.
   * @param $size
   *   File size in bytes to match. Please check the tests/files folder.
   *
   * @return
   *   List of files that match filter.
   */
  protected function drupalGetTestFiles($type, $size = NULL) {
    if (empty($this->generatedTestFiles)) {
      // Generate binary test files.
      $lines = array(64, 1024);
      $count = 0;
      foreach ($lines as $line) {
        simpletest_generate_file('binary-' . $count++, 64, $line, 'binary');
      }

      // Generate text test files.
      $lines = array(16, 256, 1024, 2048, 20480);
      $count = 0;
      foreach ($lines as $line) {
        simpletest_generate_file('text-' . $count++, 64, $line);
      }

      // Copy other test files from simpletest.
      $original = drupal_get_path('module', 'simpletest') . '/files';
      $files = file_scan_directory($original, '/(html|image|javascript|php|sql)-.*/');
      foreach ($files as $file) {
        file_unmanaged_copy($file->uri, PublicStream::basePath());
      }

      $this->generatedTestFiles = TRUE;
    }

    $files = array();
    // Make sure type is valid.
    if (in_array($type, array('binary', 'html', 'image', 'javascript', 'php', 'sql', 'text'))) {
      $files = file_scan_directory('public://', '/' . $type . '\-.*/');

      // If size is set then remove any files that are not of that size.
      if ($size !== NULL) {
        foreach ($files as $file) {
          $stats = stat($file->uri);
          if ($stats['size'] != $size) {
            unset($files[$file->uri]);
          }
        }
      }
    }
    usort($files, array($this, 'drupalCompareFiles'));
    return $files;
  }

  /**
   * Compare two files based on size and file name.
   */
  protected function drupalCompareFiles($file1, $file2) {
    $compare_size = filesize($file1->uri) - filesize($file2->uri);
    if ($compare_size) {
      // Sort by file size.
      return $compare_size;
    }
    else {
      // The files were the same size, so sort alphabetically.
      return strnatcmp($file1->name, $file2->name);
    }
  }

  /**
   * Log in a user with the internal browser.
   *
   * If a user is already logged in, then the current user is logged out before
   * logging in the specified user.
   *
   * Please note that neither the current user nor the passed-in user object is
   * populated with data of the logged in user. If you need full access to the
   * user object after logging in, it must be updated manually. If you also need
   * access to the plain-text password of the user (set by drupalCreateUser()),
   * e.g. to log in the same user again, then it must be re-assigned manually.
   * For example:
   * @code
   *   // Create a user.
   *   $account = $this->drupalCreateUser(array());
   *   $this->drupalLogin($account);
   *   // Load real user object.
   *   $pass_raw = $account->pass_raw;
   *   $account = User::load($account->id());
   *   $account->pass_raw = $pass_raw;
   * @endcode
   *
   * @param \Drupal\Core\Session\AccountInterface $account
   *   User object representing the user to log in.
   *
   * @see drupalCreateUser()
   */
  protected function drupalLogin(AccountInterface $account) {
    if ($this->loggedInUser) {
      $this->drupalLogout();
    }

    $edit = array(
      'name' => $account->getUsername(),
      'pass' => $account->pass_raw
    );
    $this->drupalPostForm('user/login', $edit, t('Log in'));

    // @see WebTestBase::drupalUserIsLoggedIn()
    if (isset($this->sessionId)) {
      $account->session_id = $this->sessionId;
    }
    $pass = $this->assert($this->drupalUserIsLoggedIn($account), format_string('User %name successfully logged in.', array('%name' => $account->getUsername())), 'User login');
    if ($pass) {
      $this->loggedInUser = $account;
      $this->container->get('current_user')->setAccount($account);
    }
  }

  /**
   * Returns whether a given user account is logged in.
   *
   * @param \Drupal\user\UserInterface $account
   *   The user account object to check.
   */
  protected function drupalUserIsLoggedIn($account) {
    if (!isset($account->session_id)) {
      return FALSE;
    }
    $session_id = $account->session_id;
    $request_stack = $this->container->get('request_stack');
    $request = $request_stack->getCurrentRequest();
    $cookies = $request->cookies->all();
    foreach ($this->cookies as $name => $value) {
      $cookies[$name] = $value['value'];
    }
    $request_stack->push($request->duplicate(NULL, NULL, NULL, $cookies));
    $logged_in = (bool) $this->container->get('session_manager')->getSaveHandler()->read($session_id);
    $request_stack->pop();
    return $logged_in;
  }

  /**
   * Logs a user out of the internal browser and confirms.
   *
   * Confirms logout by checking the login page.
   */
  protected function drupalLogout() {
    // Make a request to the logout page, and redirect to the user page, the
    // idea being if you were properly logged out you should be seeing a login
    // screen.
    $this->drupalGet('user/logout', array('query' => array('destination' => 'user/login')));
    $this->assertResponse(200, 'User was logged out.');
    $pass = $this->assertField('name', 'Username field found.', 'Logout');
    $pass = $pass && $this->assertField('pass', 'Password field found.', 'Logout');

    if ($pass) {
      // @see WebTestBase::drupalUserIsLoggedIn()
      unset($this->loggedInUser->session_id);
      $this->loggedInUser = FALSE;
      $this->container->get('current_user')->setAccount(new AnonymousUserSession());
    }
  }

  /**
   * Sets up a Drupal site for running functional and integration tests.
   *
   * Installs Drupal with the installation profile specified in
   * \Drupal\simpletest\WebTestBase::$profile into the prefixed database.
   *
   * Afterwards, installs any additional modules specified in the static
   * \Drupal\simpletest\WebTestBase::$modules property of each class in the
   * class hierarchy.
   *
   * After installation all caches are flushed and several configuration values
   * are reset to the values of the parent site executing the test, since the
   * default values may be incompatible with the environment in which tests are
   * being executed.
   */
  protected function setUp() {
    // When running tests through the Simpletest UI (vs. on the command line),
    // Simpletest's batch conflicts with the installer's batch. Batch API does
    // not support the concept of nested batches (in which the nested is not
    // progressive), so we need to temporarily pretend there was no batch.
    // Backup the currently running Simpletest batch.
    $this->originalBatch = batch_get();

    // Define information about the user 1 account.
    $this->rootUser = new UserSession(array(
      'uid' => 1,
      'name' => 'admin',
      'mail' => 'admin@example.com',
      'pass_raw' => $this->randomMachineName(),
    ));

    // The child site derives its session name from the database prefix when
    // running web tests.
    $this->generateSessionName($this->databasePrefix);

    // Reset the static batch to remove Simpletest's batch operations.
    $batch = &batch_get();
    $batch = array();

    // Get parameters for install_drupal() before removing global variables.
    $parameters = $this->installParameters();

    // Prepare installer settings that are not install_drupal() parameters.
    // Copy and prepare an actual settings.php, so as to resemble a regular
    // installation.
    // Not using File API; a potential error must trigger a PHP warning.
    $directory = DRUPAL_ROOT . '/' . $this->siteDirectory;
    copy(DRUPAL_ROOT . '/sites/default/default.settings.php', $directory . '/settings.php');
    copy(DRUPAL_ROOT . '/sites/default/default.services.yml', $directory . '/services.yml');

    // All file system paths are created by System module during installation.
    // @see system_requirements()
    // @see TestBase::prepareEnvironment()
    $settings['settings']['file_public_path'] = (object) array(
      'value' => $this->publicFilesDirectory,
      'required' => TRUE,
    );
    $settings['settings']['file_private_path'] = (object) array(
      'value' => $this->privateFilesDirectory,
      'required' => TRUE,
    );
    // Save the original site directory path, so that extensions in the
    // site-specific directory can still be discovered in the test site
    // environment.
    // @see \Drupal\Core\Extension\ExtensionDiscovery::scan()
    $settings['settings']['test_parent_site'] = (object) array(
      'value' => $this->originalSite,
      'required' => TRUE,
    );
    // Add the parent profile's search path to the child site's search paths.
    // @see \Drupal\Core\Extension\ExtensionDiscovery::getProfileDirectories()
    $settings['conf']['simpletest.settings']['parent_profile'] = (object) array(
      'value' => $this->originalProfile,
      'required' => TRUE,
    );
    $settings['settings']['apcu_ensure_unique_prefix'] = (object) array(
      'value' => FALSE,
      'required' => TRUE,
    );
    $this->writeSettings($settings);
    // Allow for test-specific overrides.
    $settings_testing_file = DRUPAL_ROOT . '/' . $this->originalSite . '/settings.testing.php';
    if (file_exists($settings_testing_file)) {
      // Copy the testing-specific settings.php overrides in place.
      copy($settings_testing_file, $directory . '/settings.testing.php');
      // Add the name of the testing class to settings.php and include the
      // testing specific overrides
      file_put_contents($directory . '/settings.php', "\n\$test_class = '" . get_class($this) ."';\n" . 'include DRUPAL_ROOT . \'/\' . $site_path . \'/settings.testing.php\';' ."\n", FILE_APPEND);
    }
    $settings_services_file = DRUPAL_ROOT . '/' . $this->originalSite . '/testing.services.yml';
    if (file_exists($settings_services_file)) {
      // Copy the testing-specific service overrides in place.
      copy($settings_services_file, $directory . '/services.yml');
    }
    if ($this->strictConfigSchema) {
      // Add a listener to validate configuration schema on save.
      $yaml = new \Symfony\Component\Yaml\Yaml();
      $services = $yaml->parse($directory . '/services.yml');
      $services['services']['simpletest.config_schema_checker'] = [
        'class' => 'Drupal\Core\Config\Testing\ConfigSchemaChecker',
        'arguments' => ['@config.typed'],
        'tags' => [['name' => 'event_subscriber']]
      ];
      file_put_contents($directory . '/services.yml', $yaml->dump($services));
    }
    // Since Drupal is bootstrapped already, install_begin_request() will not
    // bootstrap again. Hence, we have to reload the newly written custom
    // settings.php manually.
    $class_loader = require DRUPAL_ROOT . '/autoload.php';
    Settings::initialize(DRUPAL_ROOT, $this->siteDirectory, $class_loader);

    // Execute the non-interactive installer.
    require_once DRUPAL_ROOT . '/core/includes/install.core.inc';
    install_drupal($class_loader, $parameters);

    // Import new settings.php written by the installer.
    Settings::initialize(DRUPAL_ROOT, $this->siteDirectory, $class_loader);
    foreach ($GLOBALS['config_directories'] as $type => $path) {
      $this->configDirectories[$type] = $path;
    }

    // After writing settings.php, the installer removes write permissions
    // from the site directory. To allow drupal_generate_test_ua() to write
    // a file containing the private key for drupal_valid_test_ua(), the site
    // directory has to be writable.
    // TestBase::restoreEnvironment() will delete the entire site directory.
    // Not using File API; a potential error must trigger a PHP warning.
    chmod($directory, 0777);

    $request = \Drupal::request();
    $this->kernel = DrupalKernel::createFromRequest($request, $class_loader, 'prod', TRUE);
    $this->kernel->prepareLegacyRequest($request);
    // Force the container to be built from scratch instead of loaded from the
    // disk. This forces us to not accidentally load the parent site.
    $container = $this->kernel->rebuildContainer();

    $config = $container->get('config.factory');

    // Manually create and configure private and temporary files directories.
    // While these could be preset/enforced in settings.php like the public
    // files directory above, some tests expect them to be configurable in the
    // UI. If declared in settings.php, they would no longer be configurable.
    file_prepare_directory($this->privateFilesDirectory, FILE_CREATE_DIRECTORY);
    file_prepare_directory($this->tempFilesDirectory, FILE_CREATE_DIRECTORY);
    $config->getEditable('system.file')
      ->set('path.temporary', $this->tempFilesDirectory)
      ->save();

    // Manually configure the test mail collector implementation to prevent
    // tests from sending out emails and collect them in state instead.
    // While this should be enforced via settings.php prior to installation,
    // some tests expect to be able to test mail system implementations.
    $config->getEditable('system.mail')
      ->set('interface.default', 'test_mail_collector')
      ->save();

    // By default, verbosely display all errors and disable all production
    // environment optimizations for all tests to avoid needless overhead and
    // ensure a sane default experience for test authors.
    // @see https://drupal.org/node/2259167
    $config->getEditable('system.logging')
      ->set('error_level', 'verbose')
      ->save();
    $config->getEditable('system.performance')
      ->set('css.preprocess', FALSE)
      ->set('js.preprocess', FALSE)
      ->save();

    // Collect modules to install.
    $class = get_class($this);
    $modules = array();
    while ($class) {
      if (property_exists($class, 'modules')) {
        $modules = array_merge($modules, $class::$modules);
      }
      $class = get_parent_class($class);
    }
    if ($modules) {
      $modules = array_unique($modules);
      try {
        $success = $container->get('module_installer')->install($modules, TRUE);
        $this->assertTrue($success, SafeMarkup::format('Enabled modules: %modules', array('%modules' => implode(', ', $modules))));
      }
      catch (\Drupal\Core\Extension\MissingDependencyException $e) {
        // The exception message has all the details.
        $this->fail($e->getMessage());
      }

      $this->rebuildContainer();
    }

    // Restore the original Simpletest batch.
    $batch = &batch_get();
    $batch = $this->originalBatch;

    // Reset/rebuild all data structures after enabling the modules, primarily
    // to synchronize all data structures and caches between the test runner and
    // the child site.
    // @see \Drupal\Core\DrupalKernel::bootCode()
    // @todo Test-specific setUp() methods may set up further fixtures; find a
    //   way to execute this after setUp() is done, or to eliminate it entirely.
    $this->resetAll();
    $this->kernel->prepareLegacyRequest($request);

    // Explicitly call register() again on the container registered in \Drupal.
    // @todo This should already be called through
    //   DrupalKernel::prepareLegacyRequest() -> DrupalKernel::boot() but that
    //   appears to be calling a different container.
    $this->container->get('stream_wrapper_manager')->register();
  }

  /**
   * Returns the parameters that will be used when Simpletest installs Drupal.
   *
   * @see install_drupal()
   * @see install_state_defaults()
   */
  protected function installParameters() {
    $connection_info = Database::getConnectionInfo();
    $driver = $connection_info['default']['driver'];
    $connection_info['default']['prefix'] = $connection_info['default']['prefix']['default'];
    unset($connection_info['default']['driver']);
    unset($connection_info['default']['namespace']);
    unset($connection_info['default']['pdo']);
    unset($connection_info['default']['init_commands']);
    // Remove database connection info that is not used by SQLite.
    if ($driver == 'sqlite') {
      unset($connection_info['default']['username']);
      unset($connection_info['default']['password']);
      unset($connection_info['default']['host']);
      unset($connection_info['default']['port']);
    }
    $parameters = array(
      'interactive' => FALSE,
      'parameters' => array(
        'profile' => $this->profile,
        'langcode' => 'en',
      ),
      'forms' => array(
        'install_settings_form' => array(
          'driver' => $driver,
          $driver => $connection_info['default'],
        ),
        'install_configure_form' => array(
          'site_name' => 'Drupal',
          'site_mail' => 'simpletest@example.com',
          'account' => array(
            'name' => $this->rootUser->name,
            'mail' => $this->rootUser->getEmail(),
            'pass' => array(
              'pass1' => $this->rootUser->pass_raw,
              'pass2' => $this->rootUser->pass_raw,
            ),
          ),
          // \Drupal\Core\Render\Element\Checkboxes::valueCallback() requires
          // NULL instead of FALSE values for programmatic form submissions to
          // disable a checkbox.
          'update_status_module' => array(
            1 => NULL,
            2 => NULL,
          ),
        ),
      ),
    );

    // If we only have one db driver available, we cannot set the driver.
    include_once DRUPAL_ROOT . '/core/includes/install.inc';
    if (count($this->getDatabaseTypes()) == 1) {
      unset($parameters['forms']['install_settings_form']['driver']);
    }
    return $parameters;
  }

  /**
   * Returns all supported database driver installer objects.
   *
   * This wraps drupal_get_database_types() for use without a current container.
   *
   * @return \Drupal\Core\Database\Install\Tasks[]
   *   An array of available database driver installer objects.
   */
  protected function getDatabaseTypes() {
    \Drupal::setContainer($this->originalContainer);
    $database_types = drupal_get_database_types();
    \Drupal::unsetContainer();
    return $database_types;
  }

  /**
   * Rewrites the settings.php file of the test site.
   *
   * @param array $settings
   *   An array of settings to write out, in the format expected by
   *   drupal_rewrite_settings().
   *
   * @see drupal_rewrite_settings()
   */
  protected function writeSettings(array $settings) {
    include_once DRUPAL_ROOT . '/core/includes/install.inc';
    $filename = $this->siteDirectory . '/settings.php';
    // system_requirements() removes write permissions from settings.php
    // whenever it is invoked.
    // Not using File API; a potential error must trigger a PHP warning.
    chmod($filename, 0666);
    drupal_rewrite_settings($settings, $filename);
  }

  /**
   * Changes parameters in the services.yml file.
   *
   * @param $name
   *   The name of the parameter.
   * @param $value
   *   The value of the parameter.
   */
  protected function setContainerParameter($name, $value) {
    $filename = $this->siteDirectory . '/services.yml';
    chmod($filename, 0666);

    $services = Yaml::decode(file_get_contents($filename));
    $services['parameters'][$name] = $value;
    file_put_contents($filename, Yaml::encode($services));

    // Ensure that the cache is deleted for the yaml file loader.
    $file_cache = FileCacheFactory::get('container_yaml_loader');
    $file_cache->delete($filename);
  }

  /**
   * Queues custom translations to be written to settings.php.
   *
   * Use WebTestBase::writeCustomTranslations() to apply and write the queued
   * translations.
   *
   * @param string $langcode
   *   The langcode to add translations for.
   * @param array $values
   *   Array of values containing the untranslated string and its translation.
   *   For example:
   *   @code
   *   array(
   *     '' => array('Sunday' => 'domingo'),
   *     'Long month name' => array('March' => 'marzo'),
   *   );
   *   @endcode
   *   Pass an empty array to remove all existing custom translations for the
   *   given $langcode.
   */
  protected function addCustomTranslations($langcode, array $values) {
    // If $values is empty, then the test expects all custom translations to be
    // cleared.
    if (empty($values)) {
      $this->customTranslations[$langcode] = array();
    }
    // Otherwise, $values are expected to be merged into previously passed
    // values, while retaining keys that are not explicitly set.
    else {
      foreach ($values as $context => $translations) {
        foreach ($translations as $original => $translation) {
          $this->customTranslations[$langcode][$context][$original] = $translation;
        }
      }
    }
  }

  /**
   * Writes custom translations to the test site's settings.php.
   *
   * Use TestBase::addCustomTranslations() to queue custom translations before
   * calling this method.
   */
  protected function writeCustomTranslations() {
    $settings = array();
    foreach ($this->customTranslations as $langcode => $values) {
      $settings_key = 'locale_custom_strings_' . $langcode;

      // Update in-memory settings directly.
      $this->settingsSet($settings_key, $values);

      $settings['settings'][$settings_key] = (object) array(
        'value' => $values,
        'required' => TRUE,
      );
    }
    // Only rewrite settings if there are any translation changes to write.
    if (!empty($settings)) {
      $this->writeSettings($settings);